> Presumably because they feel it’s not worth the downsides of working remotely.

I've worked remotely for several employers and clients, and they all seem to hire domestically. A few had stories about their experiences with hiring foreign remote workers, and they came to to the conclusions that doing so isn't always worth the labor discounts versus just hiring domestically.

I don't think remote work is the issue here for workers in the US, because the same employers have no problem underpaying visa workers who live in the US that can't complain because getting fired means being deported.

H1B is a higher wage and much more bureaucratic hassle than hiring the same workers in their home countries, suggesting again that the employer is strongly averse to remote.